There was a flurry of activity in the OpenJDK ecosystem during the week of May 18th, 2026, highlighting three JEPs elevated from Proposed to Target to Targeted and three JEPs elevated from Candidate to Proposed to Target for JDK 27. The proposed release schedule has also been finalized.
JEPs Targeted for JDK 27
These three JEPs have been Targeted for JDK 27:
JEP 537, Vector API (Twelfth Incubator), announced here, proposes a twelfth incubation, with no substantial implementation changes since JDK 25, after eleven rounds of incubation delivered in JDK 16 through JDK 26. This feature introduces an API to "express vector computations that reliably compile at runtime to optimal vector instructions on supported CPU architectures, thus achieving performance superior to equivalent scalar computations." The Vector API will continue to incubate until the necessary features of Project Valhalla become available as preview features. At that time, the Vector API team will adapt the Vector API and its implementation to use them, and will promote the Vector API from Incubation to Preview.
JEP 534, Compact Object Headers by Default, announced here, proposes to make JEP 519, Compact Object Headers, delivered in JDK 25, the default object header layout in the HotSpot JVM. More details on Compact Object Headers may be found in this InfoQ news story.
JEP 523, Make G1 the Default Garbage Collector in All Environments, announced here, proposes to set the Garbage-First Garbage Collector (G1 GC) as the "default in all environments, rather than just server environments." If a garbage collector is not specified on the command line, the G1 GC will always be selected by the HotSpot JVM.
JEPs Proposed to Target for JDK 27
These three JEPs have been Proposed to Target for JDK 27:
JEP 538, PEM Encodings of Cryptographic Objects, announced here, proposes to finalize this feature, with changes, after two rounds of preview delivered in JDK 25 and JDK 26. This feature offers "an API for encoding objects that represent cryptographic keys, certificates, and certificate revocation lists into the widely-used Privacy-Enhanced Mail (PEM) transport format, and for decoding from that format back into objects." This JEP will support conversions between PEM text and cryptographic objects in PKCS #8 and X.509 binary formats. Changes include: a reclassification of the PEM record class to a regular class as a convenience for providing constructors that accept Base64-encoded content in byte arrays; and a rename of the DEREncodable interface to BinaryEncodable to more accurately describe the binary data stored in PEM text. The review is expected to conclude on May 27th, 2026.
JEP 536, JFR In-Process Data Redaction, announced here, proposes to enhance the JDK Flight Recorder (JFR) to redact sensitive information before the JFR completes its recording. This data may include command-line arguments, initial values of environment variables and system properties. The review is expected to conclude on May 26th, 2026.
JEP 528, Post-Mortem Crash Analysis with jcmd, announced here, proposes to extend the jcmd tool to diagnose a JVM in the event of a crash. The intent is to move this kind of serviceability into jcmd as opposed to using the jhsdb utility or the Serviceability Agent. The review is expected to conclude on May 26th, 2026.
Please note that the status of JEP 528 may have changed back to Candidate with JDK 28 as the release, but not yet formally announced. The Updated field in the JEP document is dated May 21st, 2026, one day after it was declared to be Proposed to Target for JDK 27. We will monitor and follow up as necessary.
JDK 27 Feature Set (So Far) and Release Schedule
The JDK 27 release schedule, recently approved by Mark Reinhold, Chief Architect, Java Platform Group at Oracle, is as follows:
- Rampdown Phase One (fork from main line): June 4, 2026
- Rampdown Phase Two: July 16, 2026
- Initial Release Candidate: August 6, 2026
- Final Release Candidate: August 20, 2026
- General Availability: September 14, 2026
With just just under two weeks before the scheduled Rampdown Phase One, where the feature set for JDK 27 will be frozen, 10 JEPs, including those that are Proposed to Target, are in the feature set so far:
- JEP 523: Make G1 the Default Garbage Collector in All Environments
- JEP 527: Post-Quantum Hybrid Key Exchange for TLS 1.3
- JEP 528: Post-Mortem Crash Analysis with jcmd
- JEP 531: Lazy Constants (Third Preview)
- JEP 532: Primitive Types in Patterns, instanceof, and switch (Fifth Preview)
- JEP 533: Structured Concurrency (Seventh Preview)
- JEP 534: Compact Object Headers by Default
- JEP 536: JFR In-Process Data Redaction
- JEP 537: Vector API (Twelfth Incubator)
- JEP 538: PEM Encodings of Cryptographic Objects
JDK 27 will be the second non-LTS release since JDK 25, released in September 2025.